In 1988, Illinois entered into a 5-year commitment, called the Illinois Alliance of Essential Schools (IAES), to implement the Coalition of Essential Schools (CES) philosophy in several secondary schools. This paper presents findings of a study that examined how IAES schools defined the program's nine Common Principles and the implementation strategies they devised. Data were collected through a survey mailed to the 20 participating schools (5 rural, 4 suburban, and 11 urban). Seventeen schools returned the questionnaire. Findings indicate that commonalities existed among the schools' definitions of the Common Principles and also among their strategies for implementing each principle. The definitions and strategies appeared to be consistent with those offered by the CES. However, the schools' responses lacked depth, which may have been due to the questionnaire's format. Also, the schools seemed to have a working knowledge of each of the Common Principles, but did not demonstrate a recognition of the interrelationships among the principles. They tended to treat the principles separately, rather than as an integrated whole. An implication is that school-restructuring efforts need the involvement of the entire school. The appendix contains the thematic classification system. (Contains seven references.) (LMI)